Detecting pregnancy in large agricultural animals (such as cows) is one of the most frequently performed diagnostic procedures. Timely testing of individual animals for pregnancy supports optimal management of individual animals and the maximization of farm profit for both the dairy and beef production systems.
The two most frequently used methods for pregnancy diagnosis of cattle are manual palpation of the reproductive tract (per rectum) and transrectal ultrasonography of the reproductive tract. Veterinarians and specialist animal technicians most commonly provide these services to farmers. Both procedures are invasive and practitioners require extensive training in order to undertake the procedure safely (for cow and operator).
Automated milking systems represent a completely new way of handling agricultural animals, which is likely to become more widespread, particularly in countries with high labour costs or shrinking rural labour pools. In automatic milking systems (AMS), cows are trained to circulate voluntarily through the milking system while en route from one feeding location to another. While in the milking system, milking cups are attached robotically to the cow's teats and the cow stands at rest until milking is finished—a process which takes a few minutes. This time while the animal is at rest represents an ideal time to undertake a pregnancy test on the animal.
AMS systems are most cost-effective when the usage is spread evenly over a full 24 hour period, so they require a change from batch processing of a whole herd of cows twice a day to individual processing spread over the full 24 hours. Two consequences are that, firstly, it becomes counterproductive to batch the cattle together for any reason as this upsets their training (and very often the farm is no longer optimised in either physical layout or labour availability to support herding together of cattle); and, secondly, the management process becomes dependent on individual animal data from the AMS, such as animal weight, milk production and quality, and in some cases state of oestrus (inferred by reading an animal-mounted electronic pedometer while the animal is in the AMS). It therefore would be useful and sensible to be able to test for pregnancy as part of the AMS process so that the cows are not unsettled by the batching and physical discomfort of conventional testing, and so that the data is available to be integrated with the other information used by the farm manager.
Similar developments are occurring in other animal industries and include automated gating and access points operated by individual animal RFID tags, virtual fencing and automatic drafting systems. Most are characterised by isolation of an individual animal from the group (usually via voluntary entry through a gate), identification of the animal by reading an RFID ear tag or similar and controlled and directed release. Systems that use these principles are suitable for the inclusion of an automated pregnancy testing system.
There are also many circumstances where non-dairy animals are handled using fixed-in-place machinery, such as conventional animal handling restraint systems, known in the industry as crushes or chutes and also in systems which apply restraint to the animal whilst feeding, for example, in the form of restraining head-stalls. Other examples are milking parlour bales and voluntary entry systems such as automated feeding stations. All the above systems serve to restrain the animal in some fashion and provide a suitable opportunity to conduct a pregnancy test on the animal.